1. Field of the Invention
The present invention relates to cooling computer systems, and more particularly to controlling airflow through a computer system chassis.
2. Background of the Related Art
Modern computer systems are typically modular, allowing individual hardware components to be removed and replaced with the same or other hardware components conforming to a particular standard. Even personal computers, such as laptop and desktop systems, have modular hardware devices like modular hard drives, optical drives, and system memory, along with modular fans for cooling these other heat-generating hardware devices. The larger, rack-mounted systems used in commercial applications may include many pieces of modular computer equipment mounted on racks, such as servers, power modules, network connectivity modules, and blower modules. The modular construction of rack-mounted systems makes them scalable, which allows a system to be custom-configured to achieve any size, power, and performance requirement for a given application. A rack-mounted system may use a multi-tiered cooling system that includes a computer-room air conditioning unit, along with server-level and chassis-level cooling fans and blower modules.
Moving parts in a computer can experience a greater rate of wear and a higher incidence of failure as compared with solid-state parts having no moving parts. The bearings and other moving parts used in cooling fans, for example, may lead to occasional fan replacement, and the increased incidence of failure of individual fans may limit a system's overall reliability. One method to compensate for the decreased reliability of fans is to include redundant fans. However, the use of redundant fans can add to the system's bill of materials cost, increase the cooling system complexity, and increase power consumption and power budgeting.